Breathing mask



FIG. 1 is a front view of a breathing mask showing our new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a rear perspective view thereof; and,

FIG. 7 is a bottom front perspective view thereof.

The broken line showing of linear portions of the article is included for the purpose of illustrating environmental structure with the line itself forming no part of the claimed design. 

CLAIM The ornamental design for a breathing mask, as shown and described. 